Dispersion for hot rolling aluminum products

ABSTRACT

This invention relates to an oil-in-water dispersion for the hot rolling of aluminum in which the oil phase contains from 2 to 85% fatty alcohols, from 10 to 70% high average molecular weight polybutene and from 20 to 75% of a hydrocarbon base oil having a narrow distillation range. The dispersion provides for improved lubrication properties for hot rolling and improved surface characteristics of the resultant sheet products.

United States Patent McDole et a].

'[111 3,855,136 [451 Dec. 17, 1974 DISPERSION FOR HOT ROLLING ALUMINUM PRODUCTS Inventors: Ewell E. McDole, Danville, Calif.;

Frank L. Howard, Bountiful, Utah Appl. No.: 396,813

Related US. Application Data [63] Continuation-impart of Ser. No. 198,898, Nov. 15,

1971, Pat. No. 3,770,636.

[52] US. Cl 252/495, 72/42, 252/52 R [51] Int. Cl ..C10m 1/22 [58} Field of Search 252/495, 52 R; 72/42 [56] References Cited UNITED STATES PATENTS 2,962,401 11/1960 Guminski 252/52 3,298,951 1/1967 Guminski 252/52 3,649,538 3/1972 Hotten 252/49.3

FOREIGN PATENTS OR APPLICATIONS 1,052,652 12/1966 Great Britain 252/495 1,075,196 7/1967 Great Britain 252/495 OTHER PUBLICATIONS Viscosity Conversion Monograph Primary ExaminerW. Cannon Attorney, Agent, or Firm-Paul E. Calrow; Edward J. Lynch [5 7 ABSTRACT This invention relates to an oil-in-water dispersion for distillation range. The dispersion provides for improved lubrication properties for hot rolling and improved surface characteristics of the resultant sheet products. 1

13 Claims, N0 Drawings DISPERSION FOR HOT ROLLING ALUMINUM PRODUCTS RELATED APPLICATIONS This application is a continuation-in-part of application Ser. No. 198,898 filed Nov. 15, 1971, now US. Pat. No. 3,770,636.

BACKGROUND OF THE INVENTION This invention relates to an improved lubricating composition. More particularly, it relates to a dispersion of polybutene and fatty alcohols in water useful in the hot rolling of aluminum products.

In the normal fabrication of aluminum sheet and plate materials, an ingot at a temperature of from about 650 to 950F is passed through a breakdown mill to reduce the ingot to a thickness af about 1 inch. After the breakdown passes, the 1-inch thick plate is then rolled on a multi-stand mill or a reversing mill to a thickness of about 0.1 inch. The final temperature of the product of the rolling operation normally varies between about 500 and 700F. During the rolling operation on the multi-stand mill, or the reversing mill, the workpiece and work rolls are normally flooded with a lubricant, usually an oil-in-water emulsion. The primary functions of the oil-in-water emulsion are to reduce the friction, to prevent metal-to-metal contact between the work rolls and the workpiece and to control the temperature of the work rolls.

One of the major problems encountered with the oilin-water emulsion is the small particles of aluminum and alloying elements which are removed from the surface of the workpiece and transferred to the working surfaces of the mill roll. The particles, which are highly oxidized, build up on the mill roll surface forming a coating thereon which is commonly termed roll coating. The particles of aluminum from the roll coating are subsequently retransferred to and'embedded in the surface of the workpiece. The embedded particles are commonly termed pickup." During the subsequent rolling operations, these surface imperfections tend to be hidden and it is not until the sheet material is subsequently anodized that these imperfections again appear. The imperfections are sometimes noticeable after the etching step which is normally required prior to anodizing. The surface imperfections tend to be accentuated during the anodizing process, thus rendering the The commercially available neat oil compositions employed to form an oil-in-water emulsion generally comprise a hydrocarbon oil, usually naphthenic in nasheet product unsuitable for commercial use. By increasing the lubricity ofthe oil-in-water emulsion, the pickup deposition can be minimized. However, the lubrication properties of the oil-in-water emulsion must quirements before it has any commercial applicability.

The lubricant must be capable of removing the residues of dehydrated oil from the surfaces of the work rolls and workpiece. Otherwise the residues would accelerate roll coating formation and pickup. The mixture must also prevent rust and keep the coolant piping system clean.

ture, a lubricity or wear-reducing agent, such as lauric acid, oleic acid, tricresyl phosphate, and the like, emulsifiers, such as rosin and tall oil soaps and triethanolamine oleate, and frequently a coupling agent, such as ethylene glycol to render the emulsifiers and lubricity agents soluble in the base oil. Frequently used neat oils include 591 Oil, sold by Texaco Inc., Prosol 46, sold by Mobil Oil Corporation and Tandemol K95A, sold by E. F. Houghton & Company. The oil phase of the emulsion generally comprises from 1 to 10% by weight of the emulsion. The emulsions prepared with the commercially available neat oils do provide sufficient lubrication and cooling during hot rolling, and compared with the previously used products, they significantly re duce the amount of pickup. However, the surface quality requirements for anodized sheet material have consistently increased over the years to a point where the pickup levels and the rejections therefrom are excessive when employing commercially available lubricants.

Against this background, the present invention was developed.

DESCRIPTION OF THE INVENTION The present invention relates to an improved, nonstaining lubricant composition which provides for a substantial reductionof pickup and for a substantial improvement in the lubrication, cooling and other properties. Moreover, the lubricant provides for a simplified compositional control.

The basic composition of the present invention comprises from about 2 to preferably 5 to 50%, of a long chain saturated monohydric fatty alcohol, or mixtures thereof, having from 8 to 20 carbon atoms, and

from about 15m preferably from 50 to 95%;

polybutene. The polybutene, either straighter branch chain, must have. a viscosity from about 50 to 750 SSU at F, preferably from 100 to 300 SSU at 100F. Generally, two or more polybutenes are mixed to provide the polybutene 'with the desired viscosity level. Suitable commercially available polybutenes include Oronite 6, Oronite 8 and Oronite 128 sold by the Chevron Chemical Company. Most commercially available long chain aliphatic alcohols are mixtures of fatty alcohols, such as Alfol 1216, manufactured by the Continental Oil Company, which is about 65% C12 alcohol, 23% C14 alcohol and 12% C16 alcohol.

In addition to the basic components, the lubricant of the present invention may also contain up to 5% emulsifiers, preferably anionic emulsifiers, such as triethanolamine oleate, suitable corrosion inhibitors, such as morpholinium oleate, in amounts up to 5%, and suitable antioxidants, such as butylated hydroxytoluene (BI-IT), in amounts up to 1%.

In preparing the components as a lubricant for the hot rolling of aluminum products, preferably the polybutene fatty alcohols and other materials are intimately mixed in a desired ratio, and the resultant neat oil is mixed with water. The mixing is. carried out to form an oil-water dispersion in which a substantial amount, preferably more than 30%, of the oil fraction exists as oil globules from 2 to 8 microns in size. An Oil-water lubricant with a particle size predominatly below 2 microns in size, will not have sufficient lubricity for rolling purposes, whereas an oil-waterlubricant having a particle size about 8 microns will have a lubricity which is too great for the hot rolling of aluminum, and the workpiece tends to refuse to enter the mill and to skid during rolling. The neat oil generally comprises from 1 to 10% of the oil-water dispersion or mixture. In the preferred embodiment of the present invention, the oil phase of the oil-water mixture is maintained in the proper particulate size by continually mechanically mixing the mixture. However, if desired, an emulsifier in amounts up to 5% of the neat oil, may be employed for emulsification and to maintain the proper size distribution of the oil phase, Preferably, the emulsifier is anionic because such emulsifiers allow the emulsion to be broken by adjusting the pH. It is preferred to mix these additives, such as emulsifiers, corrosion inhibitors and antioxidants, with the neat oil prior to mixing with water. Generally, the operating temperature of the dispersion is from about 90 to 140F, preferably between 90 and 120F.

The oil-in-water mixtures and emulsions of the present invention provide for a substantial reduction in the amount of pickup, greatly improve the surface brightness of the resultant sheet products, and substantially reduce the power requirements for a particular reduction in thickness.

To further illustrate the present invention, three oilin-water mixtures, or dispersions, were prepared in accordance with the present invention having the compositions described below for comparison with an oil-inwater emulsion containing 3.7% by weight of Prosol 46.

The polybutene was blend of 48% Oronite polybutene No.6 and 52% Oronite polybutene No. 8, the mixture having a viscosity of 275 SSU at 100F. The fatty alcohol was Alfol 1216. The various components were blended into the desired proportions. then dispersed in water at a temperature of 120F by a model 88 Dispersonic sonolator, made by the Sonic Engineering Company. Test strips 3 wide by /8 inch thick ofa 2024 alloy clad Z-z7r on each side with 1230 alloy were heated to a temperature of 800F, then rolled with single pass reductions of 35, 45, 55 and 65% in a 2-high Schmitz mill, utilizing the above-described lubricants in each of the reductions.

A comparison of these various lubricants is set forth below. The mill power is expressed as (mill amperes) and is interpolated to a 60% reduction. The specular reflectance measurements were taken by a Model D10 Hunter Goniophotometer at 45 incidence and the values expressed were taken in the longitudinal and transverse directions of the sheet. The amount of roll coating is expressed as milligrams of aluminum removed from the top roll by washing with aqueous caustic solution after 4 single pass reductions. The pickup with the oil-in-water mixtures or dispersions of the present invention was not detectable by visual inspection,

whereas, the pickup with Prosol 46 was objectionable.

The .two and three component mixture of the neat oil of the present invention considerably simplifies the composition control as compared with the prior art compositions. Normally, the prior are compositions contain a base oil, lubricity agents, coupling agents, emulsifiers, wetting agents, and the like. Considerable efforts were necessary to maintain the composition limitations to maintain the oil-in-water emulsion operational. Furthermore, most emulsionsneeded long periods of time, for example, from two days to one week, for a break-in period, and during this break-in period, no sheets of anodize quality could be rolled. In the preferred embodiment, the particle size of the oil globules is controlled to a large extent by the continual dispersion thereof, and therefore there is no need for a breakin period. Moreover, by simplifying the composition, the formation of degradation products is substantially minimized.

The regeneration of prior art compositions contaminated with decomposition products and particulate has not been found practical because of the high capital costs involved for equipment for separating the oil phase from the aqueous phase, and because of the large number ofingredients which would have to be restored or adjusted in concentration. Normally, the contaminated emulsions are discarded. Because the mechanically dispersed composition of the preferred embodiment readily separated into an oil phase and water phase, regeneration of the lubricant is both practical and economical.

In preparing the present invention, usually a low viscosity polybutene is mixedwith a high viscosity polybutene to form a mixture with the requisite viscosity of about 50-700 SSU at 100F.

Over extended periods of use, the oil phase of the lubricant gradually thickens due to the loss of low molecular weight polybutenes from evaporation, degradation and the like which, in turn, gradually degrades the lubricating properties of the mixture. Control of the lubricant composition at a constant level is difficult because commercially available low average molecular weight grades of polybutene have polybutene fractions with large variations in molecular weight, much larger than the polybutene fraction which is lost in use through evaporation, oxidation, degradation and the like. For example, Polybutene 6 has a distillation range at 1 atmosphere of about 300-600F. whereas the polybutene components lost in use generally have a boiling point from about 300-400F. To avoid this problem, it is preferred to use a grade of low molecular weight polybutene with a narrow distillation range wherein at least of the material is distilled in the range from about 500-650F, preferably from about 550650F at one atmosphere. (Note that polybutene depolymerizes at temperatures above about 650F.)

However, unfortunately, low molecular weight polybutene with such a narrow distillation range at reasonable costs is not presently available in large quantities. By bleeding off portions of the oil phase of the lubricant and reconstituting the lubricant with commercially available polybutenes, control of the composition at a constant level can be obtained. However, frequently, this involves discarding excessive amounts of the lubricant mixture which includes not only the polybutene but also the fatty alcohol, antioxidant agents and the like, and this may be too expensive.

It has been found that other lubricating oils with a relatively narrow distillation range can be utilized effectively instead of the low average molecular weight polybutene with a narrow distillation range and yet maintain the ease in controlling the composition of the lubricant. The hydrocarbon oil can be essentially paraffinic or naphthenic in nature or both, but generally must have a distillation range between about 500 and 725F, preferably between about 550 and 700F wherein at least 90% of the material is distilled. The oil must also have a good lubrication properties and a viscosity adequate to that when suitable amounts are mixed with a highmolecular weight, essentially nonvolatile polybutene, a mixture can be obtained having a viscosity between about 50 and 700, preferably 100-300, SSU at 100F. Suitable oils'include hydrocarbon oils, such as transformer or insulating oil, mineral seal oil and the like. A particularly suitable transformer oil is one containing large amounts of paraffinic based components and naphthenic based components.

Thus, a neat oil composition of the present invention suitable for mixing or dispersing in water which can be easily controlled over long periods of time consists essentially of about 5-50%, preferably 5-3070, fatty alcohol, -70%, preferably about -50%, polybutene having an average molecular weight above about 500 and a viscosity above about 2400 SSU at 100F, and from about 20-75%, preferably about 35-65%, ofa hydrocarbon oil having suitable lubrication properties and a distillation range wherein at least 90% of the material is distilled from about 500 to 725F, preferably 550-700F. The hydrocarbon oil should have a viscosity from about 40 to 200 SSU at -100F'. Suitable hydrocarbon oils are essentially paraffmic, naphthenic or oleffinic in nature (or combinations thereof) and may contain up to 15% by weight aromatics. Preferably, the hydrocarbon oil contains about to 70% paraffinic oil and 30 to 70% naphthenic oil. Suitable oils include transformer oil, mineral seal oil, polybutene and the like. The mixture of the high molecular weight polybutene and the said hydrocarbon oil must range from about 50-700, preferably about 100-300, SSU at 100F. The fatty alcohols are monohydric, saturated long chain aliphatic alcohols having from 8-20 carbon atoms. The high molecular weight polybutene should have a viscosity above 2400 SSU at 100F (average molecular weight above about 750) but below about 10,000 SSU at 100F. The amount of neat oil dispersed in water can range from about l to 10% of the aqueous material are lost in essentially a uniform manner, thereby minimizing problems in reconstituting the lubricant and maintaining the composition thereof on a constant level. Some loss in lubrication properties is noticed when using the nonpolybutene low viscosity hydrocarbon oils, but this slight loss in lubrication properties is less important than the ease in controlling the lubricant composition to a relatively constant operative level. One advantage to using transformer oil as the low viscosity material in the present invention rather than a low molecular weight polybutene is that transformer oil is easier to quantify by gas chromotog- 'raphy than polybutene.

As used herein, all percentages refer to weight per cent unless noted otherwise, average molecular weights are measured by Test Method SM-l 80-6, and distillation ranges are determined by ASTM Test D 86-67.

As an exampleof this embodiment of the present invention, the following neat oil was prepared.

The mixture of the high molecular weight polybutene and the transformer oil had a viscosity of about 200 -SSU at 100F.IThe transformer'oil used was Chevron lnsulating Oil 612 manufactured by the Chevron Chemical Company, the high molecular weight polybutene was Polybutene l2 manufactured by the Chevron Chemical Company and the fatty alcohol was Alfol 121-6 previously described. This neat oil was mechanically mixed with water to form a dispersion therewith, the neat oil amounting to about 3.7% of the total dispersion. After 3 hours and 6 hours of simulated hot rolling operations with the above lubricant, the dispersion was sampled and analyzed to determine the loss of the various components. It was found that over each 3 hour period, approximately 4.1% of the transformer oil had been lost. However, essentially no portion of the high molecular weight polybutene had been lost. By adding approximately 1.4% of transformer oil per hour, the composition of the hydrocarbon portion can be maintained at a relatively constant level.

The lubricating characteristics of this lubricant are 7 considerably superior to commercially available lubricants, such as an emulsion of Prosol 46 atequivalent amounts and rolling aluminum products with the presistics of the rolled products are obtained. The following example is given to illustrate some of the advantages of the present invention.

Aluminum sheets were hot rolled using the dispersion lubricant of the present invention described'in the previous example and an aqueous emulsion containing about 3.7% Prosol 46. The aluminum sheet and rolling conditions were essentially the same for both lubricants. The roll coating with the lubricant of the invention was light-medium, whereas the roll coating with the lubricant containing Prosol 46 was medium-heavy.

The rolled sheet samples were anodized in the same manner in an aqueous sulfuric acid electrolyte. The anodized samples were then tested for reflectivity which is a good indication of the surface quality of the metal. As indicated by the results set forth below, the quality of the metal surface rolled with the lubricant of the invention was far superior to that rolled with the commercial lubricant. The reflectivity was determined with a Model D10 Hunter Goniophotometer standardized at 10,000 with an aluminum mirror.

Sheet Reflectivity, 45

Lubricant Longitudinal* Transverse* Invention 530 59 Prosol 46 l 80 13 To rolling direction It is obvious that various modifications and improvegreater than about 500 and a viscosity from about 2400 to about 10.000 SSU at 100F, and about to 75% by weight of an additional hydrocarbon lubricating oil having a distillation range from about 500 to 725F at one atmosphere, which distillation range is below that of the polybutene wherein at least 90% of said hydrocarbon oil is distilled within said temperature range.

2. The neat oil composition of claim 1 wherein said hydrocarbon lubricating oil is a polybutene having an average molecular weight less than 500.

3. The neat oil composition of claim 1 wherein the mixture of said polybutene and said hydrocarbon lubricating oil having a viscosity between about 50 and 700 SSU at 100F.

4. The neat oil composition of claim 1 wherein said hydrocarbon lubricating oil is an oilselected from the group consisting of transformer oil and mineral seal oil.

5. The neat oil composition of claim l wherein said hydrocarbon lubricating oil has a viscosity between about 40 and 200 SSU at 100F.

6. The neat oil composition of claim 1 wherein said hydrocarbon lubricating oil is selected from the group consisting of naphthenic oil, paraffinic oil, olefinic oil and combinations thereof.

' 7. The neat oil composition of claim 6 wherein said hydrocarbon lubricating oil consists essentially of about 30 to paraffinic oils and about. 30 to 70% naphthenic oils.

8.The neat oil composition of claim 1 wherein the hydrocarbon lubricating oil has a distillation range from about 550 to 700F at one atmosphere.

9. The neat oil composition of claim 1 wherein the fatty alcohol is lauryl alcohol.

10. The neat oil composition of claim 1 containing about 5 to 30% fatty alcohol, 20 to 50% polybutene having an average molecular weight above about 500 and 35 to 65% hydrocarbon lubricating oil having a distillation range from about 500 to 700F.

11. The neat oil composition of claim 3 wherein the mixture of said polybutene and said hydrocarbon lubricating oil have a viscosity between 100 and 300 SSU at ing contacting the surface of the sheet and the work rolls of a rolling mill with a dispersion of water and a neat oil consisting essentially of about 5 to 50% by weight of at least one fatty alcohol selected from the group consisting of monohydric, saturated primary fatty alcohols having from 8 to 20 carbon atoms, about 20 to 60% by weight polybutene having an.average molecular weight greater than about 500 and a viscosity from about 2400 to about 10,000 SSU at 100F, and about 20 to by weight of an additional hydrocarbon lubricating oil having a distillation range from about 500 to 725F at one atmosphere, which distillation range is below that of the polybutene wherein at least of said hydrocarbon oil is distilled within said temperature range.

13. The method of claim 12 wherein said dispersion contains from about 1 to 10% of said neat oil.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Inventm-( Ewell E. McDole and Frank L. Howard It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, Line l7,"af" should be -of- Column 2, Line 67, "predominatl y" should be predominantly-- Column 3, Line 43, "was blend" should be was a blend-- Line 51, "3 wide" should be 3 inches wide-- Column 4, Line 16, "prior are" should be prior art-- Column 5, Line 22, "have a good" should be have good-- sealed this 1st day of April 1575.

\ I) Q. A t G S t i I C I DAN}? Ii-I C. 12.302? Commissioner of Patents attesting 13f ficer and Trademarks 

1. A NONSTAINING NEAT OIL COMPOSITION FOR HOT ROLLING ALUMINUM PRODUCTS SUITABLE FOR DISPERSION IN WATER CONSISTING ESSENTIALLY OF ABOUT 5 TO 50% BY WEIGHT OF AT LEAST ONE FATTY ALCOHOL SELECTED FROM THE GROUP CONSISTING OF MONOHYDRIC, SATURATED PRIMARY FATTY ALCOHOLS HAVING FROM 8 TO 20 CARBON ATOMS, ABOUT 20 TO 60% BY WEIGHT POLYBUTENE HAVING AN AVERAGE MOLECULAR WEIGHT GREATER THAN ABOUT 500 AND A VISCOSITY FROM ABOUT 2400 TO ABOUT 10,000 SSU AT 100*F, AND ABOUT 20 TP 75% BY WEIGHT OF AN ADDITIONAL HYDROCARBON LUBRICATING OIL HAVING A DISTILLATION RANGE FROM ABOUT 500* TO 725*F AT ONE ATMOSPHERE, WHICH DISTILLATION RANGE IS BELOW THAT OF THE POLYBUTENE WHEREIN AT LEAST 90% OF SAID HYDROCARBON OIL IS DISTILLED WITHIN SAID TEMPERATURE RANGE.
 2. The neat oil composition of claim 1 wherein said hydrocarbon lubricating oil is a polybutene having an average molecular weight less than
 500. 3. The neat oil composition of claim 1 wherein the mixture of said polybutene and said hydrocarbon lubricating oil having a viscosity between about 50 and 700 SSU at 100*F.
 4. The neat oil composition of claim 1 wherein said hydrocarbon lubricating oil is an oil selected from the group consisting of transformer oil and mineral seal oil.
 5. The neat oil composition of claim 1 wherein said hydrocarbon lubricating oil has a viscosity between about 40 and 200 SSU at 100*F.
 6. The neat oil composition of claim 1 wherein said hydrocarbon lubricating oil is selected from the group consisting of naphthenic oil, paraffinic oil, olefinic oil and combinations thereof.
 7. The neat oil composition of claim 6 wherein said hydrocarbon lubricating oil consists essentially of about 30 to 70% paraffinic oils and about 30 to 70% naphthenic oils.
 8. The neat oil composition of claim 1 wherein the hydrocarbon lubricating oil has a distillation range from about 550* to 700*F at one atmosphere.
 9. The neat oil composition of claim 1 wherein the fatty alcohol is lauryl alcohol.
 10. The neat oil composition of claim 1 containing about 5 to 30% fatty alcohol, 20 to 50% polybutene having an average molecular weight above about 500 and 35 to 65% hydrocarbon lubricating oil having a distillation range from about 500* to 700*F.
 11. The neat oil composition of claim 3 wherein the mixture of said polybutene and said hydrocarbon lubricating oil have a viscosity between 100 and 300 SSU at 100*F.
 12. The method of rolling aluminum sheet comprising contacting the surface of the sheet and the work rolls of a rolling mill with a dispersion of water and a neat oil consisting essentially of about 5 to 50% by weight of at least one fatty alcohol selected from the group consisting of monohydric, saturated primary fatty alcohols having from 8 to 20 carbon atoms, about 20 to 60% by weight polybutene having an average molecular weight greater than about 500 and a viscosity from about 2400 to about 10,000 SSU at 100*F, and about 20 to 75% by weight of an additional hydrocarbon lubricating oil having a distillation range from about 500* to 725*F at one atmosphere, which distillation range is below that of the polybutene wherein at least 90% of said hydrocarbon oil is distilled within said temperature range.
 13. The method of claim 12 wherein said dispersion contains from about 1 to 10% of said neat oil. 